In the related art, a known microscope apparatus scans pulsed laser light from a light source by using a scanner, relays the pulsed laser light by using a relay lens, and focuses the pulsed laser light onto a sample by using an objective lens so that fluorescence generated in accordance with a multiphoton excitation effect can be observed (for example, see Patent Literature 1).
In order to observe a large sample in high resolution with this microscope apparatus in Patent Literature 1, it is necessary to attach a low-magnifying-power objective lens with a wide actual field of view to the microscope apparatus and to increase the beam diameter of the laser light entering the objective lens.